Rep. Kevin McCarthy talks to reporters at the Capitol in December.

A version of this story appeared in CNN’s What Matters newsletter. To get it in your inbox, sign up for free here.

CNN  — 

The 118th Congress will begin on Tuesday, bringing in a new era of Republican control of the House and a high-stakes leadership fight that will determine who controls the speaker’s gavel.

Rep. Kevin McCarthy has the support of a majority of Republicans to be the GOP leader but has so far not secured enough votes to become House speaker.

What’s standing between McCarthy and the position he has long sought is a handful of conservative lawmakers. These conservatives, many members of the Freedom Caucus, don’t trust McCarthy and have not yet been convinced by him or those lobbying on his behalf, including former President Donald Trump, that McCarthy will appropriately stand up to Democrats and President Joe Biden.

Republicans will only have a slim majority – 222 Republicans compared with 212 Democrats – which means McCarthy can’t afford many defections if he is to find the 218 votes needed to make him speaker of the House.

How the day will unfold

Congress can’t really function until it has a House speaker; the position is filled on the first day of a new Congress, January 3, even before members-elect take the oath of office.

Members will meet in the morning to tie off loose ends and close the 117th Congress. Then, at noon Eastern time, the clerk of the House will gavel in the new Congress and will call a quorum. The first major order of business will be the speaker election. Democrats will place Rep. Hakeem Jeffries’ name into nomination, and Republicans are set to place McCarthy’s name.

Then the clerk will call the roll and each member will state the name of the person whom they are voting for. If no one amasses a majority of votes cast, it goes to a second ballot. If another ballot is needed, it is not clear if Congress will recess the chamber or if members will continue voting.

Members can vote for anyone they want

There’s no rule that the speaker is a House member. Members can vote for anyone, and they can protest by skipping the vote or voting “present.” The vast majority will vote for their party’s leader.

Both parties met last year to determine their leadership, with Democrats selecting Jeffries and Republicans agreeing to nominate McCarthy, but by a margin that signaled a possible floor fight ahead.

McCarthy faces a long-shot challenger: hard-right Republican Rep. Andy Biggs of Arizona. The challenge highlights the opposition McCarthy is up against and could draw votes away from him.

If no one wins a majority …

Lawmakers will continue voting until someone wins the majority. They can take successive votes on January 3. They can adjourn to horse trade and deal among themselves. But the House does not kick off the new Congress until a speaker is elected.

This is what people are talking about when they refer to a “floor fight.” It’s when House members require multiple ballots, or votes, to elect their speaker.

It’s been 100 years

The chamber of the House of Representatives is seen at the Capitol on February 28, 2022.

In the 200-plus years since the first two-year Congress met in 1789, such floor fights have occurred just 14 times, according to the House historian.

All but one of those multi-ballot speaker elections took place before the Civil War as the two-party system was evolving. Back then, floor fights were routine.

A floor fight has only taken place once since the Civil War, exactly 100 years ago, when it took nine ballots for Rep. Frederick Gillett of Massachusetts to be elected speaker in 1923.

There is some mystery here

Politico notes it’s been so long that the exact procedure if no one has a majority is a smidge unclear. A Congressional Research Service brief on electing the speaker simply says that if no one gets a majority, the vote is repeated.

There have been exceptions to the majority vote

Way back in 1849, the House had been in session so long without being able to elect a speaker – 19 days – that members voted to elect their speaker with a plurality rather than a majority. Members ultimately confirmed the plurality election with a majority vote.

The epic record for a floor fight

In 1855 and 1856, it took 133 separate votes for Rep. Nathaniel Banks of Massachusetts to be elected, again by a plurality and not a majority.

The process stretched over more than a month and included a sort of inquisition on the House floor of the three contenders. They answered questions about their view of the expansion of slavery. Read more from the House historian’s website.

It’s also interesting to read about Banks; his official House biography notes he was elected to office as a Republican, an independent, a member of the America Party and as a Democrat.

It doesn’t always require 218 votes

One important thing to remember is that McCarthy does not technically need 218 votes to become speaker. A majority of those present and voting is required to get the speakership, which is usually 218 lawmakers. But if enough people skip the vote or vote “present,” the number of votes required for a majority can drop.

House Speaker Nancy Pelosi was elected with 216 votes in 2021.

Former Speaker John Boehner won reelection to the post with 216 votes in 2015 after beating back a conservative rebellion like the one McCarthy is dealing with now.

Most of the negotiation and arm-twisting happens long before the floor vote. Pelosi got 220 votes in 2019 after turning most of the fellow Democrats who opposed her. She did so by agreeing to serve only another few years as speaker, a pledge she kept by announcing her decision in November to not seek reelection for leadership.

Ability to remove the speaker is a sticking point

Conservatives who oppose McCarthy have said they want to reinstate a dormant and arcane power to allow any member to call for a vote to remove the speaker at any time. Read more about the “motion to vacate.”

Republicans who oppose McCarthy see it as a tool for accountability. McCarthy and his allies see it as a recipe for bad governance if he is constantly at risk of losing the post that’s so difficult for him to attain.

This story has been updated with additional information.

CNN’s Clare Foran contributed to this report.